7-endo selenocyclization reactions on chiral 3-prenyl and 3-cinnamyl-2-hydroxymethylperhydro-1,3-benzoxazine derivatives. A way to enantiopure 1,4-oxazepanesElectronic supplementary information (ESI) available: Experimental details and characterization data, copies of 1H and 13C NMR spectra for all new compounds, NOESY experiments for compounds 11h, 11k, 12b, 12k, 12h, 18e, 19j and 27 and X-ray structural data and crystallographic information files (CIF) for compounds 12f, 14b, 15f, 20, 21, and

Enantiopure 1,4-oxazepane derivatives have been prepared by selenocyclofunctionalization of chiral 3-prenyl- and 3-cinnamyl-2-hydroxymethyl-substituted perhydro-1,3-benzoxazine derivatives. The 7- endo -cyclization occurs in high yields and diastereoselection. The regio- and stereochemistry of the cyclization products was dependent on the substitution pattern of the double bond, the nature of the hydroxyl group and the experimental conditions. A short and efficient procedure for the preparation of a variety of enantiopure 1,4-oxazepanes with up to three stereocenters by 7- endo -cyclization in perhydro-1,3-benzoxazine derivatives is developed.